Heat-Related Illnesses

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As many parts of the country continue to experience record high temperatures, it’s more important than ever to take steps to avoid dangerous heat-related illnesses. Cooper Clinic Preventive Medicine Physician Michael Clark, MD, discusses tips to help you identify and treat heat exhaustion and heat stroke.

Factor in the risk
Heat-related illnesses are outward physical reactions of the body when it overheats internally. Heat stroke may be the first to come to mind, but there are actually three types of heat-related illnesses:

1. Heat cramps – the least severe
2. Heat exhaustion – moderately severe
3. Heat stroke – the most severe

If left untreated, one of these can lead to a more severe form. For example, heat cramps can be easily treated by replenishing fluids and electrolytes but can lead to heat exhaustion if left untreated. Similarly, heat exhaustion can be moderately severe in nature but can lead to life-threatening conditions of heat stroke if left untreated.

Several factors can make an individual predisposed to developing a heat-related illness. “Exercising in the heat without being acclimated to a specific environment commonly increases the risk of health complications,” explains Clark. “One’s risk further increases with high-intensity activity and poor physical fitness levels.” Other factors contributing to heat-related illness and injury include:

• Heavy work equipment or clothing without proper ventilation
• High body mass index
• Sleep deprivation
• Dehydration
• Fever

Heat exhaustion
Though one of the most common heat-related illnesses, heat exhaustion can be life-threatening if left untreated. In fact, exertional heat illness is the leading cause of death among young athletes, manual laborers, firefighters and military personnel who work and train for extended periods of time in hot environments. It is crucial to be aware of the signs and symptoms to identify heat exhaustion early to reduce its severity.

Heat exhaustion occurs when the body is unable to cool its core temperature through sweating alone. The most prevalent symptoms of heat exhaustion typically include:

• Mild confusion
• Dizziness
• Loss of consciousness
• Fast breathing
• Rapid heart rate with normal blood pressure
• Sweating
• Nausea or vomiting
• Headache
• Fatigue or weakness

Taking the appropriate steps of treatment can reduce one’s risk of developing further health complications caused by heat exhaustion. First and foremost, call 9-1-1. Remove all equipment and excess clothing in order to help the body’s cooling process. Immerse the individual in a tub of cold water (35-60°F) or ice water if possible.

If ice water immersion is not available, quickly initiate alternative methods of cooling. “These methods could include applying ice packs to areas of the body near large blood vessels such as the neck, armpits and groin,” says Clark. “Continuously spraying water all over the individual’s body and blowing air using a fan over the moist skin results in an evaporative cooling effect.” The cooling methods can cease once the individual’s rectal temperature reaches 102.2°F (or 38.3-39°C).

Clark encourages continuous monitoring of mental awareness and vital signs such as heart rate, respiratory rate, rectal temperature and blood pressure until help arrives.

Heat stroke
Heat stroke is the most serious form of overheating and is considered a medical emergency. It requires hospitalization and professional medical treatment as it can quickly cause damage to the brain, heart, kidneys and muscles. The symptoms of heat stroke include:

• Altered mental state or behavior (such as delirium, hallucinations, seizures, slurred speech and difficulty walking)
• Rapid breathing
• Rapid heart rate with low blood pressure
• Dry skin (classic heat stroke) or sweating (exertional heat stroke)
• Vomiting or diarrhea
• Cardiogenic shock

Further medical examination may reveal evidence of severe complications caused by heat stroke such as:

• Disseminated intravascular coagulation—the onset of this rare but serious condition is caused by other disease or injury such as heat stroke and causes the proteins that control blood clotting to become overactive. 
• Rhabdomyolysis—the breakdown of muscle tissue releases a damaging protein called myoglobin into the bloodstream which can lead to kidney failure
• Acute renal failure—occurs when the kidneys are unable to filter waste from the blood because of dehydration
• Cardiogenic shock—where the heart is unable to pump enough blood throughout the body
• Liver failure—making this important organ incapable of filtering blood of chemicals and bile

The same cooling methods applied for heat exhaustion should be initiated immediately for heat stroke while waiting for medical care to arrive. Clark explains rapid cooling is the most effective treatment for minimizing morbidity and mortality from heat strokes. Supportive hospital therapy and treatment for various comorbidities resulting from heat stroke is likely to be required.

If you choose to participate in outdoor activities during hotter months, Clark offers these recommendations:

• Take the time necessary to allow your body to acclimate to the heat—it will serve you well in the long run
• Slowly increase the intensity and duration of your workouts
• Stay well hydrated by replenishing fluids and electrolytes during and after your activity

Applying these helpful tips as you enjoy your favorite outdoor activity can help you prevent the onset of heat-related illnesses.

To learn about Cooper Clinic preventive exams, visit the Cooper Clinic website or call 866.906.2667.